1. Field of the Invention
This invention relates to optical elements such as windows for forward-looking, infrared radiationreceiving devices that have at least one substantially flat surface adapted for exposure to incident radiation, and, within such elements, one or more doped regions having predetermined, desired, non-flat shapes or having doping concentrations that are positioned for exposure to incident radiation and adapted to focus, reflect, refract or scatter predetermined, desired wavelengths of incident radiation while transmitting other predetermined wavelengths of the incident radiation.
2. Description of Related Art
Until now, forward-looking, infrared-transmitting optical elements were required to have non-flat surfaces adapted for exposure to radiation to focus, scatter and reflect radiation such as radar while transmitting infrared radiation. Such optical elements undesirably cause some of the infrared radiation to be refracted, reflected or scattered, which limits the practicable range of curvatures acceptable for such optical elements. Further, such elements frequently produce aberrant transmissions and require additional optical elements to correct for these aberrations.